pong.go

package main

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// Copyright [2017] [Kamalavelan]

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

// http://www.apache.org/licenses/LICENSE-2.0

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// limitations under the License.

import (
	"math/rand"
	"strconv"
	"time"

	"github.com/veandco/go-sdl2/img"
	"github.com/veandco/go-sdl2/sdl"
	"github.com/veandco/go-sdl2/ttf"
)

var scoreAI int
var scorePlayer int

var velocity int32 = 5

var paddleObjects [2]*paddle
var windowHeight int32 // Some future proofing?
var windowWidth int32

type paddle struct {
	dirX        int32
	dirY        int32
	destRect    sdl.Rect
	texture     *sdl.Texture
	paddleState string
	ai          bool
}

func (p *paddle) paddleUpdate() {

	if p.destRect.Y <= 0 {
		p.destRect.Y = 5

	}
	if p.destRect.Y+p.destRect.H >= windowHeight {
		p.destRect.Y = windowHeight - p.destRect.H - 5
	}
	if p.paddleState != "none" {
		p.destRect.X += p.dirX * velocity
		p.destRect.Y += p.dirY * velocity
	}

}

type ball struct {
	dirX     int32
	dirY     int32
	destRect sdl.Rect
	texture  *sdl.Texture
}

func (b *ball) ballUpdate() {
	// fmt.Println("ballUpdate")
	b.destRect.X += b.dirX * velocity
	b.destRect.Y += b.dirY * velocity

	for _, paddle := range paddleObjects {
		if b.destRect.HasIntersection(&paddle.destRect) {
			b.dirY *= 1
			b.dirX *= -1
		}
	}
	if b.destRect.X <= 0 {
		b.destRect.X = 0
		b.destRect.X = windowWidth / 2
		b.destRect.Y = windowHeight / 2
		b.dirX *= -1
		// b.dirY *= -1
		scoreAI++
	}
	if b.destRect.X >= windowWidth {
		b.destRect.X = windowWidth
		b.destRect.X = windowWidth / 2
		b.destRect.Y = windowHeight / 2
		b.dirX *= -1
		// b.dirY *= -1
		scorePlayer++
	}
	if b.destRect.Y <= 0 {
		b.destRect.Y = 0
		b.dirY *= -1
		b.dirX *= 1
	}
	if b.destRect.Y >= windowHeight {
		b.destRect.Y = windowHeight - b.destRect.H
		b.dirY *= -1
		b.dirX *= 1
	}
}

func main() {
	sdl.Init(sdl.INIT_VIDEO)
	defer sdl.Quit()

	img.Init(img.INIT_PNG)
	defer img.Quit()

	ttf.Init()
	defer ttf.Quit()

	screenHeight := 768
	screenWidth := 1366

	window, _ := sdl.CreateWindow("Basic Pong", 0, 0, screenWidth, screenHeight, sdl.WINDOW_SHOWN|sdl.WINDOW_FULLSCREEN)
	defer window.Destroy()

	windowW, windowH := window.GetSize()
	windowWidth, windowHeight = int32(windowW), int32(windowH)

	windowSurface, _ := window.GetSurface()
	windowSurface.Free()
	renderer, _ := sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED|sdl.RENDERER_PRESENTVSYNC)
	defer renderer.Destroy()

	scoreNum := strconv.Itoa(scorePlayer)
	scoreText := "Score : "
	scoreFont, _ := ttf.OpenFont("ttf/Audiowide-Regular.ttf", 50)
	scoreTextSurface, _ := scoreFont.RenderUTF8_Blended(scoreText, sdl.Color{R: 255, G: 255, B: 255, A: 127})
	scoreTextTexture, _ := renderer.CreateTextureFromSurface(scoreTextSurface)
	defer scoreTextSurface.Free()
	defer scoreTextTexture.Destroy()
	defer scoreFont.Close()
	scoreTextRect := sdl.Rect{X: windowWidth + 10, Y: windowHeight - 60, W: 130, H: 50}

	scoreNumSurface, _ := scoreFont.RenderUTF8_Blended(scoreText, sdl.Color{R: 255, G: 255, B: 255, A: 127})
	scoreNumTexture, _ := renderer.CreateTextureFromSurface(scoreNumSurface)
	defer scoreNumSurface.Free()
	defer scoreNumTexture.Destroy()
	scoreNumRect := sdl.Rect{X: windowWidth + 130, Y: windowHeight - 60, W: 40, H: 50}

	paddleOne := paddle{dirX: 0, dirY: 0,
		destRect: sdl.Rect{X: windowWidth / 10, Y: windowHeight / 2, W: 20, H: 75}, paddleState: "none", ai: false}

	paddleTwo := paddle{dirX: 0, dirY: 0,
		destRect: sdl.Rect{X: windowWidth / 10 * 9, Y: windowHeight / 2, W: 20, H: 75}, paddleState: "ai", ai: true}

	ballOne := ball{dirX: 1, dirY: 1,
		destRect: sdl.Rect{X: windowWidth / 2, Y: windowHeight / 2, W: 25, H: 25}}

	paddleObjects[0] = &paddleOne
	paddleObjects[1] = &paddleTwo

	blue, _ := img.Load("img/blue.png")
	defer blue.Free()
	ballOne.texture, _ = renderer.CreateTextureFromSurface(blue)
	defer ballOne.texture.Destroy()

	randSeed := rand.NewSource(time.Now().UnixNano())
	randGen := rand.New(randSeed)

	renderer.Present()
	running := true
	for running {
		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
			switch t := event.(type) {
			case *sdl.KeyDownEvent:
				if t.Keysym.Sym == sdl.K_ESCAPE {
					running = false
				}
				if t.Keysym.Sym == sdl.K_w {
					paddleOne.paddleState = "up"
					paddleOne.dirY = -1
				}
				if t.Keysym.Sym == sdl.K_s {
					paddleOne.paddleState = "down"
					paddleOne.dirY = 1
				}
			case *sdl.KeyUpEvent:
				if t.Keysym.Sym == sdl.K_w {
					paddleOne.paddleState = "none"
					paddleOne.dirY = 0
				}
				if t.Keysym.Sym == sdl.K_s {
					paddleOne.paddleState = "none"
					paddleOne.dirY = 0
				}
			}

		} // control loop end
		renderer.SetDrawColor(0, 0, 0, 255)
		renderer.Clear()
		renderer.SetDrawColor(255, 255, 255, 255) //sets color for paddle

		velocity = int32((scoreAI + scorePlayer) / 3)
		if velocity < 5 {
			velocity = 5
		}
		for _, paddle := range paddleObjects {
			if paddle.ai && (ballOne.destRect.X > (windowWidth / 2)) {

				// if paddle.ai {
				// paddle.paddleState = "ai"
				if ballOne.destRect.Y >= paddle.destRect.Y {
					paddle.dirY = 1
				} else if ballOne.destRect.Y <= paddle.destRect.Y {
					paddle.dirY = -1
				}
				if randGen.Intn(10) >= 5 && sdl.GetTicks()%2 == 0 {

					// if randGen.Intn(10) >= 4 {
					paddle.paddleState = "none"
				} else {
					paddle.paddleState = "ai"
				}
			}
			renderer.FillRect(&paddle.destRect)
			paddle.paddleUpdate()
			renderer.Copy(paddle.texture, nil, &paddle.destRect)

		}

		ballOne.ballUpdate()
		renderer.Copy(ballOne.texture, nil, &ballOne.destRect)
		renderer.Present()

		scoreNumSurface, _ = scoreFont.RenderUTF8_Blended(scoreNum, sdl.Color{R: 255, G: 255, B: 255, A: 127})
		scoreNumTexture, _ = renderer.CreateTextureFromSurface(scoreNumSurface)
		renderer.Copy(scoreTextTexture, nil, &scoreTextRect)
		renderer.Copy(scoreNumTexture, nil, &scoreNumRect)
	}
}